FDTD Solutions training - Lumerical · • add an arbitrary unitary matrix to the dielectric tensor ... FDTD Solutions Workflow Example 1. ... - Set dimension to 2D - BC (Periodic

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© 2012 Lumerical Solutions, Inc.

Workflow and GUI

FDTD Solutions


FDTD Solutions features

Main window

Working with simulation objects

Object library

Monitor types

Running a simulation

Optimization and parameter sweeps

Analysis

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Main window

The graphical CAD environment is required to setup and analyze all simulations. It is also required to run all scripts.

Online Help – Layout editor

http://docs.lumerical.com/en/fdtd/ref_layout_editor.html


Showing, hiding, moving windows

Right click on menu bar (or use View menu)

Drag and reposition

windows

Close to hide

Double click on title bar to

undock/redock windows

http://docs.lumerical.com/en/fdtd/ref_layout_editor.html

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Simulation objects

Object types: •Structures •Simulation •Sources •Monitors

Online Help – Simulation resources

http://docs.lumerical.com/en/fdtd/ref_sim_obj.html


Structures and structure groups

Advanced objects can be obtained via the Object library •Structure groups

Online Help – Object library

http://docs.lumerical.com/en/fdtd/ref_layout_editor_object_tree.html

http://docs.lumerical.com/en/fdtd/ref_sim_obj.html

http://docs.lumerical.com/en/fdtd/ref_layout_editor_object_tree.html

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Structures – import options


Structures - grid attributes


http://docs.lumerical.com/en/fdtd/ref_sim_obj_attributes.html

http://docs.lumerical.com/en/fdtd/anisotropy.html

Permittivity rotation • rotate the permittivity tensor LC orientation • specify arbitrary orientations for the liquid crystal director Matrix transform • add an arbitrary unitary matrix to the dielectric tensor

Faraday Effect Magneto-Optic Kerr Effect LCD

http://docs.lumerical.com/en/next_fdtd/ref_sim_obj_attributes.html

http://docs.lumerical.com/en/next_fdtd/anisotropy.html

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Simulation


Sources

Online Help – Sources

http://docs.lumerical.com/en/fdtd/user_guide_source_movies.html

http://docs.lumerical.com/en/fdtd/ref_sim_obj_radiation_sources.html



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Basic Sources

Dipole Gaussian Plane

For source movies, please visit http://docs.lumerical.com/en/fdtd/user_guide_source_movies.html


Advanced Sources

Mode

For source movies, please visit http://docs.lumerical.com/en/fdtd/user_guide_source_movies.html

TFSF User-defined



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Monitors and analysis groups


Object library

Advanced objects can be obtained via the Object library •Structure groups •Analysis groups


http://docs.lumerical.com/en/fdtd/ref_layout_editor_object_library.html

http://docs.lumerical.com/en/fdtd/ref_layout_editor_object_library.html

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Monitors

FDTD Solutions has several monitors

Index monitors to record material properties

Movie monitors to create mpg movie files

Time monitors to record electromagnetic fields as a function of time

Frequency monitors to perform fourier transforms during the simulation

Mode expansion monitors expand field profiles into a basis set of supported waveguide modes


Index monitors

The meshed structure The true structure

)(r

kji ,,

Index Monitors record material properties

Use it to make sure you are simulating the right structure!

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Movie monitors

Use Movie Monitors for

visual aids in presentations!

observe dynamic light interaction with the structure

to develop intuition for what the simulation is doing

to make sure the simulation is doing qualitatively what you want


Time monitors

Time Monitors record E(t) and H(t)

We use time monitors to : Ensure the simulation has run long

enough

: Look for resonant frequencies by doing a fast Fourier transforms (fft) of a time signal

• Find modes of resonant cavities

• Bandstructure calculations

Normally data is recorded at single points

E(t) from a cavity simulation

fft of above data Online Help – PC cavity getting started example

http://docs.lumerical.com/en/fdtd/pc_micro_cavity_tutorial.html


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Frequency monitors

Frequency Monitors provide frequency domain (i.e. steady state or CW) data

: Fully vectorial CW data obtained via fourier transform of time domain fields.

: Obtain data at many wavelengths from a single simulation! Wavelength range must be specified in advance

: Allow us to calculate:

• transmission, reflection, absorption, scattering, spatial field profiles, far field projections, local (near) field enhancements, light extraction enhancement

Online Help – Ring resonator getting started example


|E|^2 at one frequency

Power transmission(f)


Mode expansion monitors

Mode expansion monitors expand an arbitrary field profile from a Frequency monitor using waveguide modes as a basis for the expansion

• Power coupling into waveguide modes

• S-parameter extraction to characterize components for further simulation with INTERCONNECT


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Optimization and parameter sweeps

Online Help – Optimization and sweeps

http://docs.lumerical.com/en/fdtd/user_guide_run_optimization.html

http://docs.lumerical.com/en/fdtd/user_guide_run_parameter_sweep.html


Analysis of results

Browse Object

tree.

Red icon means

the object has

simulation data

Results

viewer

Right click to

calculate and

visualize results

http://docs.lumerical.com/en/fdtd/user_guide_run_optimization.html

http://docs.lumerical.com/en/fdtd/user_guide_run_parameter_sweep.html

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Basic analysis - Visualizer

Online Help – Visualizer

http://docs.lumerical.com/en/next_fdtd/ref_analysis_visualizer.html

Export data as

jpeg, text file, or

copy and paste

into Excel

View data in

tabular format

and select all or

portion of data

to export

Select data to

display from

Attributes and

Parameters

sections


Script file editor

Right click on

menu bar (or

use View menu)

Advanced analysis with scripting

Script prompt Script workspace

Script favorites

Online Help – Scripting resources

http://docs.lumerical.com/en/fdtd/ref_scripts_scripting_language.html

http://docs.lumerical.com/en/fdtd/user_guide_scripts.html

http://docs.lumerical.com/en/next_fdtd/ref_analysis_visualizer.html

http://docs.lumerical.com/en/fdtd/ref_scripts_scripting_language.html

http://docs.lumerical.com/en/fdtd/user_guide_scripts.html

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FDTD Solutions Workflow Example

1. Create Physical Structures 2. Set Simulation Parameters 3. Define Sources 4. Define Monitors 5. Run Simulation 6. Analyze Results 7. Repeat if necessary

We will go through these steps in the following example.


Convergence testing

Use a coarse mesh for initial simulations

: Memory scales as 1/dx3

: Simulation time scales as 1/dx4

Online Help – Testing convergence

http://docs.lumerical.com/en/fdtd/user_guide_testing_convergence.html

http://docs.lumerical.com/en/fdtd/user_guide_testing_convergence.html

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Simple example

Part 1: Measure the transmission through a 50 nm thick slab of Si on glass from 400 to 800nm

1. Physical Structures - Set drawing grid to 25nm - Create structures

2. Simulation Area - Set dimension to 2D - BC (Periodic in x, PML in y) - “x span”=400nm, “y span”=1 micron - Mesh accuracy of 2

3. Sources - Plane wave source, from glass

side to air - Wavelength 400 to 800nm

4. Monitors - Movie monitor

- Index monitor over entire structure - Time monitor in Si layer - Transmission/Reflection monitors “R”, “T” (100 frequency points each) - Full profile over entire structure (5 frequency points)


Simple example

Recalculate and look at the FDTD mesh

: Do we need a mesh override region?

What happens at the interface?

: Which material is used here?

For precise control set mesh order correctly

Be careful to extend structure into the

PML boundary condition

Silicon Glass

The

interface

point

will be

Silicon!

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Simple example

Check memory requirements!

Check material fits

Save simulation file under name simple_example.fsp

Run simulation

: Note when the simulation “auto-shutoff” occurs

• Can we reduce the maximum simulation time for the next simulation?


Simple example

Analyze results

: Run the movie: movie.mpg

: Visualize monitor results by right-clicking object in Objects Tree or selecting the object and right-clicking the result in Results View window

: Plot Ez vs time (auto-shutoff?)

: Image n and k. Is the structure correct?

: Plot transmission vs wavelength

: Image |Ez|2 at 3 different wavelengths

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Simple example

Part 2: Set up a parameter sweep to sweep the thickness of the Si layer from 50 nm to 100 nm over 5 points.


Simple example

Visualize sweep results : Change the plot type to 1D

Line plot to get transmission spectrum at a certain thickness

: Select the Si_thickness parameter and move the slider to plot the transmission spectrum at each thicknesses

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Where to find help and examples

Online help at www.lumerical.com/fdtd_online_help : New features summary

: Installation manual

: Getting started

: Reference guide

: Script function reference

: User guide

: Application help

Application summaries : www.lumerical.com/fdtd_applications


Getting help

Technical Support

: Email: [email protected]

: Online help: www.lumerical.com/fdtd_online_help

• Many examples, user guide, full text search, getting started, reference guide, installation manuals

: Phone: +1-604-733-9006 and press 2 for support

Sales information: [email protected]

Find an authorized sales representative for your region:

: www.lumerical.com and select Contact Us

http://www.lumerical.com/fdtd_online_help

http://www.lumerical.com/fdtd_applications

mailto:[email protected]

http://www.lumerical.com/fdtd_online_help

mailto:[email protected]

http://www.lumerical.com/

Documents

FDTD Solutions training - Lumerical · • add an arbitrary unitary matrix to the dielectric tensor ... FDTD Solutions Workflow Example 1. ... - Set dimension to 2D - BC (Periodic